The aim of this study is to understand the factors that drive what citizen's intention to use the City113 mobile application, an e-government system for citizen report. Initially, a preliminary an open-ended questions survey has been conducted to explore what factors motivate citizens to use the City113. The findings factors were compared to existing prominent technology adoption models (including TAM, DOI, UTAUT, TRA, TPB, and DTPB) and suggested the Decomposed Theory of Planned Behavior (DTPB) model with a new construct specific to gamification called playfulness is the most suitable model for representing user acceptance of the e-government citizen report application. We perform the analysis using SPSS and SmartPLS for validity and reliability test and inferential analysis for validating the model. The data were collected using questionnaire targeting citizens in 7 sub-districts of Surabaya city. The number of sample size is calculated using Slovin formula collecting 156 valid responses. This study suggests that the most significant determinant of user's intention to use the City113 mobile application is attitude (R2 = 0.435, t=5.238). There are only two factors influencing the attitude towards using the City113: Perceived Ease of Use and Perceived Usefulness. Citizens may have a positive or negative feeling towards using an e-government citizen report system mainly influenced by their perceptions on whether the system is easy to use and whether the system will deliver benefits for them or not.</p